Effect of an escape vent in accordion-shaped traps on the catch and size of Asian paddle crabs Charybdis japonica in an artificial reef area

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• 作者：Peng Zhang 张鹏 ; Chao Li 李超 ; Wentao Li 李文涛…
• 关键词：Charybdis japonica ; accordion ; shaped trap ; escape vent ; selectivity ; artificial reef area
• 刊名：Chinese Journal of Oceanology and Limnology
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：34
• 期：6
• 页码：1238-1246
• 全文大小：831 KB
• 刊物主题：Oceanography;
• 出版者：Springer Berlin Heidelberg
• ISSN：1993-5005
• 卷排序：34

文摘

Accordion-shaped traps are widely used in China to catch the Asian paddle crab Charybdis japonica but traps of conventional design often catch juvenile crabs. A new type of accordion-shaped trap with an escape vent (L×W=4.3 cm×3.0 cm) was designed and a comparative study between the newly designed and conventional traps was performed in the artificial reef area of Zhuwang, Laizhou Bay, China from June to August 2012. The mean catch per unit effort (CPUE) of undersized crabs was significantly lower in the vented traps than in the conventional traps (paired t -test, n=30, P<0.001), while the CPUE of marketable crabs was significantly higher in the vented traps (paired t-test, n=30, P<0.001). The mean size of crabs (carapace length) caught in the vented traps was significantly larger than in conventional traps (paired t-test, n=29, P<0.001). The ratio of undersized crabs was 35.05±2.57% in conventional traps and 12.53±0.69% in vented traps (significantly lower, paired t-test, n=29, P<0.001). Therefore, a 4.3 cm×3.0 cm escape vent was considered appropriate for C. japonica fishing in the artificial reef area. This finding will assist the development of more sustainable and efficient crab fishing methods using accordion-shaped traps.